A capo is a well-known assistance tool, used by a player of a stringed instrument to adjust a tone of the stringed instrument. The capo may be applied onto a plurality of stringed instruments, including a steel-string acoustic guitar, a classical guitar, an electric guitar, a banjo and more, which has a neck and a plurality of strings extending following a direction of the neck. The neck comprises a fingerboard portion next to the strings and a neck back next to the fingerboard. The fingerboard portion comprises slightly raised a plurality of frets on the fingerboard (that is, a front surface of the neck) and extending laterally. During using, the capo clamps the neck and keeps the strings leaning onto the fingerboard, especially onto one of the frets set following the direction of the fingerboard, to adjust a pitch generated by the strings through decreasing an effective length of the string.
Capos currently on market may be generally divided into a plurality of types including a toggle capo, a spring-clamp capo, a screw-on capo and a rolling capo.
The toggle capo (FIG. 1) is generally made by plastics, thus having a relatively worse quality, and easy to get broken.
The spring-clamp capo (FIG. 2) owns a design for easy and convenient use, and it may be operated by a single hand of the player, which owns a stable quality, and a constant flexibility. However, a clamping force of the capo may not be adjusted according to a different situation.
The screw-on capo (FIG. 3) is mainly made of a stainless steel material, the clamping force thereof may be adjusted through a spiral screw, to be loose or tight, however, it requires both hands of the player to operate an adjustment to reach a best usage state.
The rolling capo (FIG. 4) is also called a glider rolling capo. It has a character of being able to change a tune freely in a middle of playing, however, due to it is over flexible, an unstable performance may be leaded.
Therefore, the prior art needs to be improved and developed.